.relMiddleBox {
  position: relative;
}
.relMidAbs {
  /*user defined start*/

  border: 1px solid #f00;
  background: #fc0;
  width: 200px;
  height: 160px;
  /*user defined end*/

  position: absolute;
  top: 50%;
  left: 50%;
  margin: -80px 0 0 -100px;
}
